Tuesday, May 2, 2017

Climate of Complete Incomprehension

I finally got around to reading the NY Times new “responsible conservative”, Bret Stephens’, call for skepticism and moderation on climate change. He adopts an attitude that exudes reasonableness and rejection of hubris. Complicated modeling is an uncertain business and often fails; just look at Hilary Clinton’s Big Data campaign gurus. Climate change is such a difficult, uncertain business, so why don’t liberals just back off and stop invoking a “scientific consensus” to bludgeon common people who don’t think decarbonization is the be-all and end-all?

If this is the outer limit of right-wing sanity, we’ve really got our work cut out for us.

First off, the guy seems to live in a binary, pre-probability universe. At least, that’s the only sense I can make of a paragraph like

Anyone who has read the 2014 report of the Intergovernmental Panel on Climate Change knows that, while the modest (0.85 degrees Celsius, or about 1.5 degrees Fahrenheit) warming of the earth since 1880 is indisputable, as is the human influence on that warming, much else that passes as accepted fact is really a matter of probabilities. That’s especially true of the sophisticated but fallible models and simulations by which scientists attempt to peer into the climate future. To say this isn’t to deny science. It’s to acknowledge it honestly.

Well, yes. I’ve read the latest assessment reports and the ones that preceded them, and it’s true that each claim is assigned a rough probability. But to counterpose “fact” and “probability” is to really not understand how modern science works. Science is always a matter of probability. When I do a statistical test, I don’t sum it up by saying that it proves that my result is a “fact”, but that I can assign a provisional probability to it, or a confidence interval or (best yet) a plausible probability distribution around my best guess of what’s going on. This is the basis for all modern work in the empirical sciences, and singling out the use of probabilities by IPCC as somehow demanding less credence or urgency is to demonstrate his own ignorance.

And there’s more. Implicit in the entire piece is that the uncertainty is one-sided, that climate change might be as bad as the models predict, or it might be a more minor problem. It never dawns on him that probability distributions have two tails, and the consequences of foregoing climate action might be much more severe, catastrophic even, than the mean prediction suggests. This makes it clear that Stephens’ use of “probabilistic” to denigrate concern on climate change is pure ideology: he’s using the word to blow smoke over the issue rather than to illuminate it.

This is just op-ed #1 from their new guy, but it already looks like the Times has hired a hack.